What is the smallest insect on Earth? -Laurenz, 8, Molino, Philippines 

Dear Laurenz,

When I saw your question, I set out to explore with my bug net and a magnifying glass. I was searching all around for tiny insects when I ran into my friend Laura Lavine, a Washington State University scientist who studies bugs.

She said there are nearly a million different kinds of insects on Earth. The smallest of all the known ones are called fairyflies.

Like all insects, fairyflies have six legs. And like most insects, they also have wings. Some swim under water and use their wings as paddles. Their wings are also a bit hairy. It also turns out the fairyfly isn’t truly a fly. It’s a kind of wasp.

Screen Shot 2016-04-04 at 9.05.13 AM“They are almost impossible to spot with the naked eye,” Lavine said.

In fact, fairy flies are nearly 400 times smaller than the typical ant. And they are about two or three times the width of a human hair.

I imagine finding a fairyfly would be like finding a needle in a haystack. You’d have to keep a sharp eye out.

I started to wonder how exactly entomologists could spot such tiny fairyflies or other kinds of small insects in the wild. For example, a couple years ago scientists discovered a new kind of fairyfly in Costa Rica. It was named Tinkerbella nana after the fairy from Peter Pan.

Lavine explained that scientists often use nets or traps to catch the insects. Sometimes they have to sift through dirt and litter, or decaying leaf matter, a teaspoon at a time to see what they can find.

Scientists can also use what they know about the insect’s behavior and habitat to help track them down. Fairyflies, despite their cute name, are killer insects. They lay eggs inside a host insect’s egg. When the fairyfly’s egg hatches, it eats the host egg. If we keep our eyes out for their host bugs and their eggs, we might also find the fairyfly.

Fairyflies are important for the environment, Lavine added. Farmers and scientists can use fairyflies to help get rid of bigger insects that damage grape vines, blackberries and sugar cane. These tiny creatures help us do a big job.

The insect world is filled with interesting critters. Thinking about the smallest insect also made me wonder about the biggest one on our planet. The biggest bug is a giant walking stick. It’s almost 2 feet long. But who knows? There might be even bigger insects or even smaller insects we haven’t discovered yet crawling around on our planet.

Thanks for your question, Laurenz. It reminds me that even the small things can inspire us to wonder big.

Sincerely,

Dr. Universe